This invention relates generally to packaging machinery such as machinery for squaring or erecting cases, and more specifically to horizontal magazines or hoppers for feeding packaging blanks.
Packaging machines, case erectors in particular, often utilize horizontal magazines, which store a reserve or group of flattened cases. As the lead case of the group is removed into the machine for processing, the magazine's feeder apparatus moves the group of cases towards the removal position. This places the new lead case in position for removal. The feeder apparatus typically consists of a single plate, or other substantial structure, which is in contact with and applying pressure against the rearmost case of the group. These magazines tend to fall into two basic types, related to their reserve capacity.
The first type of magazine is typically referred to as the “standard equipment” magazine, which has a capacity of approximately one hundred cases. This magazine is usually a basic, low-cost unit powered by a stored energy type of drive, such as gravity or spring tension. This type of magazine is typically inclined, so that the cases tend to flow downhill. A crude temporary support means is provided to facilitate reloading.
The second type of magazine is typically referred to as the “extended capacity” magazine, capable of handling two hundred cases or more. This magazine is usually a costly and complex upgrade, powered by electricity, compressed air, or fluid power, and may also incorporate automated controls to simplify operation and reloading. This invention relates to embodiments of the first type of magazine, to which there are currently several disadvantages, such as those listed below.
Retracting the feeding apparatus is a manual operation, typically involving reaching over the magazine and applying considerable effort. This is strenuous and awkward for the operator. Additionally, retracting the feeding apparatus can disturb or upset the remaining cases in the magazine, causing them to slide out of the magazine and disrupt operation of the case erecting machine.
The temporary support means used to hold the group of cases while loading typically does not adequately feed the cases. This can cause erratic feeding and jamming of the case erecting machine while the magazine is being loaded.
There are typically side guide rails provided to guide the outer edges of the cases. When loading, the additional cases must be lifted over these side guide rails from a position alongside the magazine, creating an awkward and difficult maneuver for the operator. When the magazine is mounted in an inclined manner, sloping downward towards the removal position, loading is made even more difficult.
Most magazines must be adjustable to accommodate a wide range of case sizes. An attempt is made to size and position the feeder apparatus to accommodate the widely varying area of the flattened case. This leads to a compromise in the reliability of the feeder apparatus, relative to where a particular case size falls in the range of the magazine. The largest cases are often most poorly served.
Most designs use only a single driving and/or braking mechanism to control case feeding. The lead case position is sensed or detected at only one point (the center of the bottom edge typically), if it is at all. This permits a good deal of variance in the attitude of the lead case as it is driven into the removal position. It may sit skewed, at an angle from top to bottom, or side to side, or both.
As the magazine empties, the decreasing pressure on the lead case causes an inconsistency in the final stopped location, at the removal position of the magazine. Particularly in case erecting machines that use a rotary motion to remove and square-up the case, this affects the squareness of the delivered case.